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Former Member

Scheduling of Update Statistics wrt DB Check

Hello,

I have a question that is rattling my brain but I cannot find anything in SAP help or SAP notes.

Recently, while monitoring our customer SAP systems running on Oracle db, we found that we were getting repititive MISSING_STATISTICS alerts daily. We checked and found that both 'Update Statistics' and 'DBCHECK' were scheduled to run daily at the following times:

The current schedule for DEV system is

01:00 UpdateStats

06:00 CheckDB

The current schedule for QAS system is

03:00 UpdateStats

04:00 CheckDB

Someone suggested to us that the solution is to change this schedule in a manner that CheckDB runs 1 hr before UpdateStats.

But this doesn't make sense to me because if CheckDB runs before UpdateStats, then the CheckDB will still throw the same missing_statistics alerts the next day instead of same day. As a result, we will still be getting these alerts, even if they come one day late.

My question is:

1. Is that person correct in suggesting this change of schedule?

2. Is there any way, we can avoid getting these repititive alerts and find a permanent fix for this problem?

Any suggestions and/or references to SAP Notes/help topics are most welcome.

Regards,

Shitij

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4 Answers

  • Sep 26, 2008 at 07:12 AM

    Hello,

    First, thank you. At least you searched for information before posting 😊

    Then, to answer the questions I'd need more information.

    I have to say that changing the schedule does not make any sense.

    I'd investigate a little more

    • Can you tell us, your DB version, SAP version and BRCONNECT version and patch level?

    -> first I'd get one of the objects where you get the error MISSING_STATISTICS (you can post one example here)

    -> then I'd check in DB21 if there is any "special" condition for its statistics calculation (you can post the DB21 line here)

    -> then I'd check the brconnect stats log and check if the object appears there and what is reported for it.

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    Former Member
    Sep 26, 2008 at 11:41 AM

    just a thought is till how long does ur update stats run ??

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  • Sep 26, 2008 at 11:46 AM

    1. do not update stats while there is a lot of update activities going on, especially on BW systems.

    2. run update stats, then run checkDB quickly after.

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    • Former Member

      Hi,

      Try to analyse this schedule .This should solve your issue:

      1. Investigate which tables need new statistics

      Run : Check optimizer statistics

      Mon - Thu and Sunday 23:00

      2. Create new statistics for tables chosen by the previous job

      Run : Refresh optimizer/space statistics

      Mon - Fri 01:00

      3. Create statistics for all tables

      Run : Create new optimizer/space statistics

      Sat 01:00

      4. Check the tree structure for all tables/objects in the DB

      Run : Check database structure (all objects)

      Sat 23:00

      Regards,

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    Former Member
    Sep 26, 2008 at 01:18 PM

    are the mising stats error for the same tables .

    Are these tables included in normal update stats schedule.

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